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/* Copyright (C) 1993, 1994, 1997 Aladdin Enterprises. All rights reserved.
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This software is provided AS-IS with no warranty, either express or
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implied.
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This software is distributed under license and may not be copied,
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modified or distributed except as expressly authorized under the terms
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of the license contained in the file LICENSE in this distribution.
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For more information about licensing, please refer to
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http://www.ghostscript.com/licensing/. For information on
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commercial licensing, go to http://www.artifex.com/licensing/ or
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contact Artifex Software, Inc., 101 Lucas Valley Road #110,
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San Rafael, CA 94903, U.S.A., +1(415)492-9861.
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*/
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/* $Id: gsht.h,v 1.5 2002/06/16 08:45:42 lpd Exp $ */
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/* Public interface to halftone functionality */
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#ifndef gsht_INCLUDED
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# define gsht_INCLUDED
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/* Client definition of (Type 1) halftones */
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typedef struct gs_screen_halftone_s {
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float frequency;
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float angle;
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float (*spot_function) (floatp, floatp);
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/* setscreen or sethalftone sets these: */
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/* (a Level 2 feature, but we include them in Level 1) */
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float actual_frequency;
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float actual_angle;
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} gs_screen_halftone;
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#define st_screen_halftone_max_ptrs 0
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/* Client definition of color (Type 2) halftones */
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typedef struct gs_colorscreen_halftone_s {
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union _css {
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gs_screen_halftone indexed[4];
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struct _csc {
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gs_screen_halftone red, green, blue, gray;
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} colored;
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} screens;
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} gs_colorscreen_halftone;
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#define st_colorscreen_halftone_max_ptrs 0
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/* Procedural interface */
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int gs_setscreen(gs_state *, gs_screen_halftone *);
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int gs_currentscreen(const gs_state *, gs_screen_halftone *);
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int gs_currentscreenlevels(const gs_state *);
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/*
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* Enumeration-style definition of a single screen. The client must:
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* - probably, call gs_screen_enum_alloc;
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* - call gs_screen_init;
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* - in a loop,
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* - call gs_screen_currentpoint; if it returns 1, exit;
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* - call gs_screen_next;
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* - if desired, call gs_screen_install to install the screen.
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*/
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typedef struct gs_screen_enum_s gs_screen_enum;
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gs_screen_enum *gs_screen_enum_alloc(gs_memory_t *, client_name_t);
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int gs_screen_init(gs_screen_enum *, gs_state *, gs_screen_halftone *);
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int gs_screen_currentpoint(gs_screen_enum *, gs_point *);
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int gs_screen_next(gs_screen_enum *, floatp);
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int gs_screen_install(gs_screen_enum *);
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#endif /* gsht_INCLUDED */
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